He becomes the first major hiring of John Wringe, the former chief operating officer of WPP's Red Cell network, who joined earlier this year to grow the group's business.
The group's plan is to have advertising work accounting for half of its business within the next 12 to 18 months and says it is close to hiring a high-profile creative director to accelerate the process.
The group, established nine years ago by the former Holmes & Marchant chief executive, John Sandom, gained its reputation as a packaging and design specialist. Its clients include Unilever Bestfoods, Kraft, Quaker, ICI, Guinness and SC Johnson.
At present, the group's advertising activity is limited with most work farmed out to freelance creatives.
Clinton was previously the managing director of the integrated agency BH McCann and his work will include harnessing senior specialists within the group into a single, integrated service.
"Simon is not only an adman with 15 years experience but he's also very enthusiastic about pursuing non-advertising solutions, Wringe said.
Clinton's arrival coincides with a development programme being led by Wringe, which is expected to include a UK acquisition and a joint venture in the US on the back of existing client business.